Last updated: 6/8/2016​By popular demand, here is a glossary of railroad, MBTA, and Keolis terms that are relevant to commuter rail operations. I'll link to this post from the "helpful information" page, and I'll try to keep this updated. Let me know if you have a term or abbreviation you need defined. It will always be a work in progress.

These definitions are primarily intended for the casual 'civilian' with an interest in railroad terminology, so I have intentionally simplified some definitions. So if you're a die-hard railfan or someone studying for your NORAC rules test, these definitions may not be sufficient for you. But if I have made any errors, please let me know.

As always, I'm greatly indebted to the contributors on railroad.net who made both direct suggestions for this page and also indirectly contributed by imparting knowledge onto me or piquing my curiosity to go learn more.

ACSES: Pronounced "access" or "ack-sess." Advanced Civil Speed Enforcement System. This is only used on the Northeast Corridor / Providence line. It is a form of positive train control (see below) which builds on the "cab signal" concept (see below) to automatically control a train. Basically, ACSES can initiate an automatic brake application within a set amount of time if the engineer doesn't do what a speed restriction or signal requires. ACSES was implemented when the Northeast Corridor (see below) was upgraded to accommodate high speed Acela service. As a condition of being allowed to operate trains at speeds up to 150 mph, the Federal Railway Administration required positive train control (see below) and ACSES is the system that was developed. It is used not only on the Acela trains - all trains (freight, commuter rail, and Amtrak) operating on the Northeast Corridor are required to have ACSES. The system uses fixed equipment along the tracks and also special equipment on the train in order to function properly. Due to the use of all commuter rail equipment on any line (see this discussion for more details), all of the south side (see below) equipment has ACSES - and the equipment is needed in both the control car and the locomotive. Some control cars do not have ACSES, and those control cars are kept on the north side. The bad news is that the ACSES equipment is understandably some of the most complex components on a train, and having it breakdown can take a locomotive or control car out of service. Wikipedia article here.

Alerter: see "Deadman Switch" below.

Assistant Conductor: A uniformed crew member who works under the direction of the conductor. Depending on ridership loads and the length of the train, different numbers of assistant conductors are assigned to different train trips. Assistant conductors collect tickets and operate the traps (see below) and doors, but they can also assist with other functions, such as brake tests, connecting or disconnecting train sets, or operating manual switches. A train is not required (by law or regulation) to have assistant conductors. Sometimes referred to as Trainmen or Brakemen (which are both older, primarily freight train terms). Keolis Assistant Conductors are members of the Transport Workers Union (an affiliated union).

Automatic Block Signal System (ABS): To mitigate the chance of train collisions, an automatic block signal system divides the rail line into discrete sections known as blocks - each separated by a set of signals. The signal system then displays appropriate signals to indicate where trains are - without the intervention of a dispatcher. Between interlockings (see below), the wayside signals or cab signals (see below) display lights that tell the engineer where another train is (or what the next signal is). For example, let's imagine a rail line with three blocks. The first block is occupied by a train. Therefore the signal between block one and two will display red - indicating to a following train that block one is occupied. The next signal away from the first train (between blocks two and three) will show a yellow signal - indicating that block two is clear, but that block one is occupied and therefore the signal between block two and one is red. A train passing this yellow signal will know that they can expect a red signal at the next block. How does the signal system know where the trains are? It uses the axles of the trains to complete a 'track circuit' between each rail to detect the presence of a train (see video at link below for illustration of this concept). This is a gross over simplification of ABS, but it illustrates the point without filling up this page. This system has been in use for many years, and has proven to be reliable and robust (although nothing is perfect). On the Framingham-Worcester line, the section from Boston to Framingham is a wayside automatic block signal system (wayside meaning that the signals are displayed on signal masts (towers) next to the tracks). In this section, each block is about one mile long. From Framingham to Worcester, a cab signal system (see below) is used. An interesting feature of the ABS system is that because it is independent of the CTC (see below), the dispatcher can neither see nor control what the wayside ABS signals are displaying. The dispatcher can only control the signals at interlockings or control points.ABS system Wikipedia article here. This is an old and corny video, but it does a good job illustrating the ABS concept (and it's only two minutes long!). The automatic block signal system was invented before traffic signals for cars, and when viewed in that context, the yellow signal of the railroad ABS system makes much more sense than the yellow signal on traffic lights. Since trains are forced to follow a certain path (between switches), the system can be configured to definitively tell a train what the signals will be displaying at the next block. So a yellow ABS signal meaning that the next signal is red makes much more sense (at least to me) than a momentary yellow for cars at a traffic light. But you can see how the railroad ABS system was adopted for car traffic signals. A wayside automatic block signal along the track is referred to as an "automatic," and each is numbered with a decimal number on a small placard under the signal lights: the digits before the decimal number indicate the closest mile marker, while the digits after the decimal indicate which track and what direction. For example, "Automatic 10.2E (east)" is the automatic block signal near mile marker 10 on track 2 for eastbound trains. This automatic signal actually exists and is just east of Auburndale station. You can actually see it on google maps street view from the Mass Pike. Engineers are required to verbally (over the radio) state the condition ("name") of a signal that is anything less than "clear," so you may hear an engineer saying "approach at automatic ten, track 2, east" after which the conductor will acknowledge the information.

Beacon Park: Former CSX freight yard in Allston. CSX sold the land to Harvard University in May 2003. The MBTA and CSX have perpetual rights to use the yard for railroad (commuter rail or freight) purposes. CSX relocated their freight operations to other locations such as Worcester and Westboro and their use of the Beacon Park yard for freight operations ceased in February 2013. See this post for references.

Bell (1): There is a warning bell on the exterior of the locomotive and control coach. It must be rung to warn people of the train's approach at certain places such as grade crossings, stations, around track workers, and when someone is observed near the tracks. Most of the warning bells are driven by the compressed air system, and the engineer manually activates the bell from the control stand. This bell has nothing to do with the bell at each control stand (see below).

Bell (2): The backup communication system utilizing a bell at each control stand (in the locomotive and the control coach). See "Brake Test" below. This bell also rings in the case of a problem in the locomotive - for example, if the HEP (see below) fails, the bell will ring to make sure the engineer is aware. This bell has nothing to do with the bell on the exterior of the locomotive or control coach (see above).

Blind Coach (or car): a passenger carrying coach that is NOT a control coach. All 'blind' coaches have three digit numbers. They are formally known as "BTC" for Blind Trailer Coach. One or two digits or numerals are added after the BTC abbreviation to designate what 'model' or 'series' the coaches are from. A roster of coaches is available here.

Boston & Albany: The Boston & Albany is one of the oldest rail lines in North America, and we get to ride on it every day! The Framingham-Worcester commuter rail line is the easternmost 45 mile section of the former Boston & Albany railroad. The first section from Boston to West Newton opened in 1834 - along the same alignment used today! The line was fully operational from Boston to Albany in 1841. It is also referred to as the "Boston Subdivision" as this is what it (the entire line from Albany to Boston) was called when Conrail and now CSX used it / owned it as part of their network of national freight service. Wikipedia article here.

Boston Engine Terminal (BET): The old but most commonly used name for the Commuter Rail Maintenance Facility (CRMF) in Somerville, where most of the maintenance for locomotives and coaches is conducted. This is the primary repair facility where the most complicated work can be performed on trains, including changing engines on locomotives, replacing wheel sets on locomotives or coaches, and everything smaller than those tasks. Since it is on the north side, trains needing repairs or maintenance that can't be done on the south side must make the somewhat complicated trip across the Grand Junction (see below) to get from the south side to the BET.

Brake Test: Before departing from a terminal (beginning of a trip), a brake test must be conducted to confirm that the compressed air brake system is operating properly. A crew member goes to the rear of the train (which could be the control car or the locomotive, depending on the direction of operation), and the engineer releases and applies the train air brakes from the controls at the front of the train. The crew member at the opposite end of the train can observe the compressed air pressure in the brake system on a gauge and reports back to the engineer if the system functions properly. This report can be by radio or by using the bell system - there is a bell at the control stand of both the locomotive and the control car that can be rung from the other location. This communication method predates radios and is still installed on passenger trains as a backup. You may hear the bell being rung to acknowledge the brake test if you are in the control car at the start of a trip (such as at South Station awaiting departure). During the brake test, the train won't roll away because the brakes on the locomotive are separate and remain applied. The train may roll slightly during the brake test because the couplers (actually draft gear) may 'stretch' or 'contract' allowing the train to get slightly longer or shorter, making some cars roll back or forward.A brake test is also required after resetting the brake system after any application of the emergency brake function and also after coaches or locomotives are connected to makeup a train set. When a train is connected to another train (for example, to 'rescue' a dead set), a brake test would also be required.

Bubble: The little office shed thing at the foot of track 10 at South Station. It looks like a temporary structure, and is raised off the ground and accessed by a small stairway. The trainmaster (see below) works here.

Bustitution: Slang term for substituting train service with buses.

Cab Signals: The next generation of automatic block signaling (see above), cab signals move the display of signals from the masts or towers along the tracks into the cab. A special display in the cab of the locomotive (or control coach) gives the engineer a continuous indication of the signal currently in effect in the block (see ABS above) that the train is in. This system increases safety because the engineer does not have to rely on memory to remember the last signal passed - it is right there to see. And changes in signal indication can be transmitted much quicker to the engineer, without the delay of waiting for the wayside signal to come into view. On the Framingham-Worcester line, the section from Framingham to Worcester has a cab signal system in use (and therefore there are no wayside ABS signals). Wikipedia article here. See also "ACSES" and "Positive Train Control."

CETC: Pronounced "see-tek" - Centralized Electrification and Traffic Control. Technically this is the formal name of the CTC (see below) system used by Amtrak for the entire Northeast Corridor. This system controls not only the trains on the Northeast Corridor via ACSES (see above), but also the electrical loads and electrical distribution associated with the Amtrak electrified train system. Since the dispatchers working the MBTA / Keolis south side lines share the dispatch theatre at South Station with the Amtrak Northeast Corridor dispatcher, the South Station dispatch theatre is commonly referred to as CETC, but this is not technically accurate, since "CETC" is technically a computer system. And since the Framingham / Worcester line doesn't have any electrification, nor is it owned or operated by Amtrak, the dispatch system for the Framingham / Worcester line isn't part of CETC. The newly renovated South Station dispatch theatre opened on June 26, 2015. Picture here. I toured the old dispatch theatre years ago. Photo here. This picture shows a dispatch screen and how to read it. The track layout at South Station has changed, but the theory of how to read the screen is still the same.

Channel: Railroads are allocated approximately 95 distinct frequencies for communications. The AAR (Association of American Railroads) manages the assignment of these frequencies. For convenience, each frequency is assigned a channel number. Each railroad radio has the capability to transmit and receive on different channels, so when referring to channels, they are typically referred to in a pair. Keolis conductors and assistant conductors carry portable radios with a digital LED display that shows what channels they are tuned to - so if you look at the radio you will see "20-20" or something similar. For the Framingham Worcester line, there are only two primary channels that are in use:"Worcester Line" dispatcher - channel 20/20, 160.410 MHz. In use from Worcester to CP COVE near South Station."Terminal Dispatcher" - the Amtrak South Station terminal dispatcher, channel 64/64, 161.070 MHz. In use from CP COVE into South Station. You may hear the train crew saying something like 'going over' on the radio as a reminder for all of them to change the channel on their radio as they depart or approach South Station near CP COVE. Other channels that are of interest:"Mechanical Help Desk" - channel 90/90, 161.460 MHz. Usually referred to as just the "help desk." This is used for train crews to talk to Keolis management engineers for assistance troubleshooting problems with equipment. The help desk is actually located at the CROCC in Somerville (see above). "Framingham North Yard" - channel 64/64, 161.070 MHz. The CSX freight yard in Framingham uses this channel for yard operations. There is a yard manager in the office / operations building north of the Framingham train station who coordinates yard operations and goes by the call sign "Framingham North Yard." (Since it is so far away from South Station, there is no interference with the South Station dispatcher). "Framingham Subdivision" - channel 21/21, 160.425 MHz. See "Framingham Subdivision" below. Dispatchers can talk to train crews across wide distances because there are multiple transmit and receive antennas across each train line. The dispatcher can control what antenna is used to transmit and receive and selects an antenna based on the proximity of the train. An antenna station is located at the Framingham station - look for the big antenna at the east end of the station! Communications can be sent to and from the antenna stations and the dispatcher's desk via dedicated telephone lines, a separate radio system, microwave signals, or dedicated fiber optic cables owned by the railroad. I have no idea how the MBTA / Keolis does it. More information on railroad frequencies here. See "Dispatcher" definition below for more frequencies.

Clock Facing: A schedule where the service departs at the same minute of each hour. For example, if a train left Worcester at 6:00 AM, 6:30 AM, 7:00 AM, 7:30 AM, 8:00 AM and so on, that schedule would be said to be 'clock facing.' The advantage is that a rider doesn't need to memorize a complicated schedule - only the particular 'minutes' that a train stops at their particular station. This kind of schedule can be setup with any interval, and the interval does not need to be even. For example, a schedule with trains arriving / departing at x:00, x:23, x:35, and x:50 would be odd but still be clock facing, as long as that pattern repeated every hour (for at least a couple of hours). Obviously most clock-facing schedules have equal intervals, not only to maximize the logic but also the distribution of train sets. Wikipedia article here.

Control Coach (or car): a passenger carrying coach, outfitted with controls for the engineer to be able to operate the train in "push-pull" mode (see below). Similarly, they have headlights, a horn, and other features that allow them to be used at the front of a train set. The control coach also has red 'marker' lights that are illuminated to indicate the location of the rear of the train when the train is being pulled. When operated in the 'push' mode, the engineer is at the control stand of the control coach and there is nobody in the cab of the locomotive. Therefore note that the locomotive must have specialized equipment to allow for 'remote' operation from the control coach.All MBTA commuter rail control coaches have four digits as the number of the coach, and the first digit is always "1." Of course there is an exception to every rule: coaches 1600 through 1624 were originally control coaches but their controls have been deactivated and are now just blind trailer coaches.Control coaches are formally called "CTC" for Control Trailer Coach. One or two digits or numerals are added after the CTC abbreviation to designate what 'model' or 'series' the coaches are from. A roster of coaches is available here. Since every train set / consist needs a control car (and usually each set only has one), each control car has an AED. For more information on why the MBTA added AED's to each train, read this blog post, especially the last few paragraphs. Control Coaches are sometimes deridingly nicknamed 'coffin cars' because passengers sitting in a control coach do not have the buffer of a locomotive in the event of a collision. Fatalities and injuries, therefore, are more likely to the occupants of control coaches than coaches further back in the consist (when the train is in 'push' mode and the control car is in the front). For example, all five passenger fatalities aboard the MetroNorth train 659 collision in February 2015 were in the control coach. MetroLink, in Los Angeles, implemented a policy of placing a locomotive in front of all control coaches in response to a similar train vs. vehicle collision. NOTE that one of the contributing factors in the MetroNorth accident and the subsequent fatalities was the under-run third rail, which is NOT present on the MBTA commuter rail system. Also note that MetroLink has MANY more grade crossings than the MBTA, and therefore is at much higher risk for train-vehicle collisions. Remember that train travel is VERY safe, and you're more likely to get killed when you jaywalk across the street after you get off the train in Boston. I sit in the control coach every day without worrying about it. But you will notice that the MBTA only uses control coaches for passengers during rush hour when the most seats are needed. The control coach is the first coach to be 'closed off' to passengers when ridership is lighter. Control coach Wikipedia article here.

Control Stand: The console of controls used by the engineer to operate the train. The control stand is on the right hand side (known as the 'engineer's side') of the locomotive or control coach (as viewed from the train operating forward). This means the train is operated from the opposite side than a typical American car (where the driver sits on the left).

Conductor: The person in charge of a train. On the commuter rail, the conductor is a uniformed member of the crew, and also collects tickets in the passenger coaches. However, their primary responsibility is the safe operation of the train. No train can operate without a conductor. The conductor must be qualified for the rail line they are working on - qualifications involve knowing the locations of signals, interlockings, speed limit changes, and various other physical conditions of the line. Each train set has one conductor. See also Engineer and Assistant Conductor. Keolis Conductors are members of the Transport Workers Union (an affiliated union).

Consist or Set: a combination of a locomotive and coaches that forms a train..

CP: Controlled point. A location on the railroad where the signals are controlled by the dispatcher (believe it or not, the other signals are not controlled by the dispatcher - see "Automatic Block Signal" above). On the Framingham Worcester line, each CP also has crossover switches so a train can change from one track to another. The controlled points along the Framingham Worcester line are known as "CP XX" where "XX" is the closest mile marker number, such as "CP 21." This is an artifact of Conrail and CSX terminology that persists along the Framingham-Worcester line. Other MBTA commuter rail lines have actual names for their controlled points, such as "Forest," "Plains," "Thatcher," etc. The only exceptions on the Framingham Worcester line are the two controlled points closest to South Station. Just outside of South Station is controlled point "TOWER ONE" and just west of that is controlled point "COVE" (both of which are under the jurisdiction of the South Station terminal dispatcher, so some would argue those controlled points are not actually on the Framingham-Worcester line). The locations of the controlled points on the Framingham-Worcester line are shown on the map I created.

CP Yard: Name of the yard adjacent to the former General Motors assembly plant (now Adesa car auction facility) in South Framingham. CP stands for "Constructive Placement," which is a term related to demurrage. After the GM plant ceased building cars, an autorack unloading facility near the CP Yard was still used for offloading new cars from freight trains (and transloaded onto tractor trailers for final delivery to dealerships). That freight service ended in 2009, with the autorack service relocated to the relatively new CSX autorack facility in East Brookfield, MA. The switch from the Boston and Worcester mainline to the CP Yard is just west of the Framingham station and within the limits of the CP 22 interlocking. The CP yard is sometimes used for 'overflow' freight traffic when Nevins Yard or the Framingham North Yard do not have capacity. The line leading to the CP Yard was also known as the Holliston Industrial Track, since it led to Holliston and eventually Milford. The rail line south of Whitney Street / Eliot Street in Sherborn / Ashland has been formally abandoned as a railroad, and portions of the Holliston Industrial Track in Holliston and Milford are now the Upper Charles Rail Trail. At one time, the Holliston Industrial Track was connected to the Framingham Worcester mainline with a 'wye' (see below) connection. The west side of the wye is all that remains - the east side of the wye connected to the mainline just west of the original Framingham station building (now the Deluxe Depot Diner). The right of way still exists between the parking lot for Republic Plumbing Supply and the Town of Framingham commuter parking lot. This Town of Framingham parking lot is actually on the 'infield' of the wye - between both legs of the wye. Before push-pull commuter train operations, MBTA commuter trains would use this wye to reverse direction back to Boston.

CROCC: "Commuter Rail Operations Control Center." Located in Somerville, this is where all theMBTA/Keolis north side commuter rail dispatchers are located (all of the south side line dispatchers are located at South Station). The Mechanical Desk or "Help Desk" (AAR channel 90/90) is also at the CROCC (for both north and south sides).

C&S: Control and Signal department. This is the department or division of Keolis that is responsible for maintaining and repairing the signals, switches, crossing gates, and other control type devices on the railroad (where owned by the MBTA).

CTC (1): Centralized Traffic Control. A computerized dispatch system, where a dispatcher controls the switches and some signals (see "Automatic Block Signals" above) for a rail line. See "Dispatcher" below. A CTC can be programmed to prevent the dispatcher from aligning some switches and signals in an arrangement that would cause a conflict (or collision) between trains. CTC is a generic term (see also CETC above).

CTC (2): Control Trailer Coach (see "Control Coach" above).

Deadhead: See "Non-revenue" below.

Deadman Switch: With only one person at the controls of the train, something is needed to mitigate the risk of a runaway train due to the incapacitation of the engineer. Having a deadman switch that is continuously held down (like the handle on a lawn mower) is not ideal, since it can be defeated by leaning on it (and the leaning could be by an incapacitated engineer!). So the deadman switch in use on modern locomotives and control coaches is a button that must be momentarily pressed at certain time intervals. The button begins by flashing to 'request' a push, and if it isn't pushed in a certain amount of time, it starts sounding a noise. Eventually, after it starts flashing and then sounding, if it still isn't pushed, it sends a signal to the controls of the train to stop the engine and apply the brakes to stop the train. The deadman switch is sometimes called an alerter, although technically speaking the alerter is something connected to the deadman switch system but different than the actual deadman switch. Wikipedia article here.

Defect Detector: A device at a fixed place on the railroad that monitors passing trains for problems with their equipment. They can be used to detect dragging equipment (something broken and dragging, which isn't good), or overheated wheel bearings, among other problems. There is one defect detector on the Framingham Worcester line just west of the Ashland station and another in Grafton. After a train passes the defect detector in Ashland (and there are no defects detected), a really corny automated voice comes over the radio and says "CONRAIL ASHLAND MASSACHUSETTS TRACK xx NO DEFECTS OVER." Even though CSX took over operation of the line from Conrail in 1999, and the MBTA purchased the line in 2011, the silly voice still says Conrail. If a defect detector detects a defect, the voice will transmit on the radio and tell the engineer to stop the train. The engineer is obligated to stop the train and have the crew inspect the train to identify (and correct, if possible) the defect. The advantage to railfans is that defect detectors are very useful to determine where a train is when listening to the radio via a scanner. Wikipedia article here.

Delay in Block: Have you ever seen those "D.I.B" signs near some stations? That stands for "delay in block" (which is rule 504 in the current NORAC rules). This is one of the more complex issues in this glossary, and it took me a while to get my head around it. So please read "Automatic Block Signal," "Home Signal," and "Distant Signal" first. Delay in Block is a concept invented as a result of a fatal train accident - the 1996 collision of a Maryland Commuter Rail train ("MARC") with the Amtrak Capitol Limited. You can read about that here. But to explain DIB, let's recreate the MARC accident as a hypothetical situation on the Framingham Worcester line. If you need to, use the map to get some idea of what we're talking about. First, the setup: CP 21 is the home signal in downtown Framingham. West Natick station is within the block between the CP 21 home signal and the automatic signals at milepost 18 (westbound automatic 18 is therefore the 'distant' signal to CP 21). Scenario:A westbound passenger train passes the automatic 18 signal with an approach indication. This approach indication at automatic 18 indicates that the interlocking at CP 21 is either occupied or 'not ready' and a stop signal should be expected at CP 21. As planned, our westbound passenger train stops at the West Natick station. Not being able to see CP 21 from the West Natick station (it's around a curve and miles away), our westbound passenger train departs West Natick and FORGETS that they had passed an approach signal and accelerates to track speed. This human error is somewhat understandable - if there hadn't have been a stop, the train would have started decelerating after the approach signal and the engineer's thought process would have been continuous to the stop signal at CP 21. But the station stop interrupts this thought process and the natural action after the station stop is to accelerate up to track speed. By the time the engineer sees the stop indication at CP 21, it is too late and the train can't stop at CP 21. It passes through the CP 21 signal and collides with a train within the CP 21 interlocking. Which is generally a bad thing. But wait! That can't happen! We have DIB! The Delay in Block rule is exactly for this problem. Simply put, when the Delay in Block rule is in effect, a train that makes a station stop between a distant and a home signal must then approach the home signal PREPARED TO STOP at no more than 40 mph. So with DIB in effect, let's go back to our scenario: our westbound train making the station stop at West Natick is not allowed to accelerate to track speed leaving West Natick, and is reminded of this by the yellow "DIB" sign just after West Natick station - right where the engineer is sitting during the West Natick station stop. If making the West Natick stop, the train has to be prepared to stop before it reaches CP 21, no matter what the automatic 18 said. Problem solved. If you understand this concept, you pass, you're an official foamer (see below).

Diesel-Electric: All MBTA commuter rail locomotives are diesel-electric locomotives. Unlike with a highway truck, where the diesel engine is mechanically coupled (via a driveshaft) to the drive wheels, a diesel-electric locomotive uses a combination of a diesel engine (the "prime mover") and electricity to move the train. The prime mover transmits rotational energy to a generator that produces electricity. This electricity is transmitted (via cables) to the electric traction motors that turn the drive axles of the locomotive. Note that the 'diesel-electric' type of locomotive does not refer to the electricity produced by the head end power (HEP) unit. A freight locomotive without a HEP is still a diesel electric locomotive, since the 'electric' in 'diesel-electric' refers to the electricity used by the traction motors. This website has many pages that go further into detail regarding the diesel electric locomotive.

Dispatcher: The individual responsible for managing the traffic flow of a rail line. For the Framingham-Worcester line, there is a single Dispatcher (for each shift) for the "Worcester Mainline" (more details below). This Dispatcher sits at the CETC theatre in South Station. From this position, the Dispatcher can talk to train and maintenance crews via the radio system (see "channel" above) and also operate switches and signals at interlockings. The Dispatcher cannot remotely control or stop trains. The Dispatcher is not responsible for assigning equipment and not necessarily responsible for determining what to do when trains break down. The Dispatcher does NOT control 'customer service' related functions such as the LED signs at stations, the T-Alerts text messages, or the @MBTA_CR twitter feed (all of those are managed by the Keolis Customer Service department). Each Dispatcher reports to the Assistant Chief Train Dispatcher and Chief Train Dispatcher. In the case of out-of-the-ordinary situations, the Chief Train Dispatcher would collaborate with the Trainmaster, "Incident Commander," mechanical staff, and/or the engineering department (depending on the particular situation) to implement workarounds for managing train traffic.The primary responsibility of each Dispatcher is the safe movement of the traffic on 'their' tracks. The secondary responsibility is the on-time movement of the traffic on 'their' tracks according to the published schedule (actually the employee time table, which is more comprehensive than the schedules we see). Keolis, Amtrak, and Pan AM (PAR) train dispatchers are members of the American Train Dispatchers Association (an affiliated union). See also "CETC" above. The radio frequency that each dispatcher uses is listed below - which have been updated as of 2/1/2016 when some new channels were activated. See "Channel" definition above for more information about radio channels. <this information compiled from a variety of sources, including railroad.net and scan-ne.net>South Side DispatchersThere are a number of dispatchers at the CETC theatre in South Station for the entire south side (and beyond), as listed below. Each dispatcher is referred to as a 'desk.' "Exclusive" and "inclusive" below indicates who controls a particular interlocking. "Amtrak Terminal" dispatcher: Amtrak employee. Responsible for South Station. Limits of responsibility are on the Framingham-Worcester and Providence / Northeast Corridor lines from CP COVE (inclusive) into South Station and on the Old Colony and Dorchester branch lines from TOWER ONE (inclusive) into South Station. Channel 54/54, 160.920 MHz"Worcester Mainline" dispatcher: Keolis employee. Responsible from CP COVE (exclusive) to CP 45 (exclusive) in Worcester. Channel 20/20, 160.410 MHz"Old Colony" dispatcher: Keolis employee. Responsible for Old Colony lines (Greenbush, Plymouth / Kingston, and Middleboro) lines from CP CABOT (exclusive) southward. Channel 41/41, 160.725 MHz"Corridor" dispatcher: Amtrak employee. Responsible for the Providence line / Northeast Corridor from CP COVE (exclusive) to CP JUNCTION (inclusive) (near Canton, MA). Channel 54/54, 160.920 MHz"Main Line" dispatcher: Amtrak employee. Responsible for the Providence line / Northeast Corridor from CP JUNCTION (exclusive) to Cranston, RI (except coverage extends to Mystic CT when "South County" is off-duty, which is Monday - Friday 3 PM - 11 PM and weekends as noted below). Channel 54/54, 160.920 MHz"South County" dispatcher: Amtrak employee. Not on duty Monday - Friday 3 PM to 11 PM nor on weekends. When not on duty, territory covered by "Main Line" dispatcher. Responsible for the Northeast Corridor from Cranston, RI to Mystic CT (obviously not dispatching MBTA / Keolis trains, just included here for completeness). Channel 54/54, 160.920 MHz"Dorchester" line dispatcher: Amtrak employee. Responsible for Dorchester Branch from CP TOWER ONE (exclusive) to CP SOUTH BAY (inclusive) and also the Middleboro Main Line (Old Colony) from CP TOWER ONE (exclusive) to CP CABOT (inclusive). Channel 92/92, 161.490 MHz"Branch line" dispatcher: Keolis employee. Responsible for the Dorchester Branch from CP SOUTH BAY (exclusive) to Readville, and also responsible for the Needham, Stoughton and Franklin branches. Channel 54/54, 160.920 MHz"Mass Coastal" dispatcher: Mass Coastal is actually a subsidiary of Iowa Pacific Holdings. Iowa Pacific conducts dispatching of the Mass Coastal lines from their central office (so obviously this dispatcher isn't sitting at the CTEC in South Station). This dispatcher is responsible for the Mass Coastal controlled lines which the "Cape Flyer" uses to get from Middleboro to Hyannis. Mass Coastal also dispatches the "Framingham Secondary," which includes the section of track where the Foxboro / Gillette Stadium MBTA station is. Channel 21/21, 160.425 MHz.North Side Dispatchers: Just for completeness, here is the list of dispatchers for the North Side. Keolis dispatchers for the North Side are in the CROCC (see above), while the Pan Am dispatchers are at the Pan Am offices. Each dispatcher is referred to as a 'desk.' "Exclusive" and "inclusive" below indicates who controls a particular interlocking. "Terminal" dispatcher: Keolis employee. Channel 87/87, 161.415 MHz. Responsible for:1) Fitchburg main line from North Station to CP SWIFT (inclusive) 2) Western Route (Haverhill line) from North Station to CP FELLS (inclusive) - but see "Valley" dispatcher below3) Eastern Route (Newburyport line) from North Station to CP READING JUNCTION (inclusive) 4) New Hampshire Route (Lowell line) from North Station to CP SOMERVILLE JUNCTION (exclusive)5) Grand Junction track (see "Grand Junction" below)"Valley" dispatcher: Keolis employee. Channel 14/14, 160.320 MHz. Responsible for the Western Route (Haverhill line) from CP TOWER A (exclusive) to CP CPW-WJ (Wilmington Junction) (exclusive). This desk is only staffed from Monday-Friday 7AM-11PM. At other times, territory is dispatched by "Terminal" dispatcher or "Boston East" dispatcher as described elsewhere."Boston East" dispatcher: Keolis employee. Channel 14/14, 160.320 MHz. Responsible for:1) Gloucester branch from CP READING JUNCTION (exclusive) to Newburyport2) Western Route (Haverhill line) from CP FELLS (exclusive) to CPW-WJ (Weekends and 11PM-7AM daily)"Boston West" dispatcher: Keolis employee. Channel 32/32, 160.590 MHz. Responsible for:1) New Hampshire Route (Lowell line) from CP SOMERVILLE JUNCTION (inclusive) to CPF-BY (Bleachery) (exclusive)2) Wildcat Branch3) Fitchburg Route from CP SWIFT (exclusive) to CPF-WL (Weekends and 11PM-7AM daily)"Fitchburg" dipsatcher: Keolis employee. Channel 32/32, 160.590 MHz. Responsible for Fitchburg line from CP SWIFT (exclusive) to CPF-WL (exclusive). This desk is only staffed from Monday-Friday 7AM-11PM. At other times, the territory is dispatched by the "Boston West" dispatcher. "PAR District #2" dispatcher: Pan Am Railways employee. Channel 70/94, 161.160 MHz/161.520 MHz. Responsible for:1) New Hampshire Route (Lowell line) from CPF-BY (Bleachery) to CPF-LO (Lowell)2) Western Route (Haverhill line) from CPW-WJ (Wilmington Junction) (inclusive) to CPF-273 (Plaistow / State line)3) Danvers Industrial Track4) Medford Industrial Track"PAR District #3" dispatcher: Pan Am Railways employee. Channel 70/94, 161.160 MHz/161.520 MHz. Responsible for Fitchburg line from CP CPF-WL (The Willows) (inclusive) to Water St/Fitchburg (soon to be extended west to Wachusett)

Distant Signal: The 'last' signal before a home signal (see below) at an interlocking. If there are no automatic block signals between interlockings, a home signal could also be a distant signal for the next interlocking. This exact situation exists on the Framingham Worcester mainline at CP 3 westbound, CP 4 eastbound, CP 21 westbound, and CP 22 eastbound (and maybe others). A distant signal has a yellow sign with a black "D" on it to indicate it is a distant signal. A distant signal designation is used to indicate to an engineer that they are approaching a home signal and certain conditions / considerations apply. See also "NORAC" below and "Delay In Block" above.

Double: Slang term for a bi-level coach. The different models of bi-level coaches have from 173 to 185 seats, depending on exact configuration and manufacturer. Kawasaki built the majority of the doubles, with the first order of coaches entering service in 1990-1991. Hyundai-Rotem built the newest 'doubles' which have all been delivered. However, some of the new "Rotems" are at Davisville, RI undergoing warranty modifications, while some coaches are still due to rotate down to that facility for the warranty modifications. The Rotems have been widely criticized for shoddy workmanship, and the entire order was delivered very late. A roster of coaches is available here.

Double Draft: Two trainsets coupled together and operating as one train. On some lines, a scheduled double draft (usually non-revenue, see below) is used to position equipment for the AM commute, either because of a lack of layover space or some other operational consideration. For example, a double draft would depart Boston very early in the morning and upon its arrival at the end of the line, the double draft would be split into two separate trains for service back into Boston as two different trains. In years past, a double draft has been used for this purpose on the Framingham-Worcester line, but the current schedule does not include any scheduled double drafts on this line. Double drafts are also used / encountered when locomotives fail - typically the next train operating behind the dead train will 'tie onto' the dead train and push it along the remainder of it's trip. The problem with this is that if both trains are carrying passengers, the double draft will typically have to make two stops at each station, since the double draft is too long for all the coach doors to line up with the station platform.

DTMF: Technically, DTMF stands for Dual Tone Multi Frequency. You know it as the noises that your phone makes when you push the different number keys. The radio system in use on the Framingham Worcester line has DTMF capability. Each radio has a dial pad on it, and it works just like your telephone - push the buttons and the tones are transmitted over the radio. The reason this is interesting for us is that the Concord Street grade crossing in Framingham is manually controlled with DTMF tones in the eastbound direction. As a train pulls into Framingham station headed east, it will encounter a stop signal at the far east end of the platform - before the Deluxe Diner Depot and before Concord Street. This is actually CP 21. If the dispatcher has aligned the CTC system properly, the engineer can enter a two digit DTMF code into the radio to 'request' that the signal system close the Concord Street crossing gates and then give the train a clear signal at CP 21. The advantage to this is that the Concord Street crossing gates can remain up and allow vehicle traffic to proceed normally through downtown Framingham while the train is in the station being loaded with passengers. And it eliminates the need for the train crew to call the dispatcher and ask him or her to activate the signal. Before the MBTA bought the line, the same system existed, but without DTMF tones. There is a little box at the east end of the platform (one for each track) with a push button inside that has the same functionality. The push button still exists and can be used as a backup to the DTMF method. Also interesting to note is that once the sequence is initiated, the train must proceed past the CP 21 signal within a set period of time, otherwise the signal reverts back to stop. It then can't be reactivated for a certain period of time (sometime called 'burn down'). For this reason, the train crews are very reluctant to stop the trains to pick up late passengers when leaving Framingham eastbound.

Engineer: the operator of the train. The engineer reports to the conductor, who has overall responsibility and authority for the train's operation. The engineer sits at the control stand of the locomotive (for outbound trips) or the control stand in the control coach (for inbound trips), where he/she uses the levers and controls to operate the train. The engineer usually conducts primary radio communications with the dispatcher. On MBTA / Keolis trains, the engineer does not wear a uniform. Most engineers are conductors prior to being promoted to engineers (after extensive classroom training and on the job training). Each engineer must be qualified for each rail line they work on, and those qualifications must be kept current and updated periodically. Qualifications involve knowing the locations of signals, interlockings, speed limit changes, and various other physical conditions of the line - essentially the engineer must memorize the entire route. Keolis Engineers are members of the Transport Workers Union (an affiliated union).

Engine Burn: Term used to describe damage to rail caused by wheel slip. An extreme example is pictured here(supposedly a freight train had the train brakes on but the locomotive was allowed to operate). Typically the damage is much less severe, such as this example from an observant Worcester line rider. This damage was on Track 1 at the Grafton station on 11/17/15. See "wheel slip," "slippery rail," and "sand" definitions also.

EOT or ETD: End of Train device. Not used on commuter rail services, since the control coach provides the same functionality. The EOT is used on freight trains as a replacement for cabooses. The EOT provides information to the engineer in the cab of the train regarding certain operating parameters such as brake air pressure. Some EOT's allow the engineer to apply the emergency brakes to the rear of the train at the same time as the front, enabling more rapid brake application. Wikipedia article here.

Flat or Single: Slang term for a single level coach. The different models of single level coaches vary in seating capacity from 88 to 127. The primary reason for the wide range of seating capacity is because the MBB (Messerschmitt-Bolkow-Blohm) manufactured single level coaches have 2 seats on both sides of the aisle (2x2 seating), while the other coaches have 2 seats on one side of the aisle and 3 seats on the other (2x3 seating). The oldest coaches originally built by Pullman-Standard in 1978-1979 were rebuilt in 1996. Other than that, the rest of the singles were all manufactured between 1987 and 1990.

Foamer: Term used to refer to a railfan, usually with derogatory connotations. I wear my "foamer" title with pride! Since many railfans have detailed technical knowledge regarding the operations of a railroad, they can be very effective spotters for safety issues and anything out-of-place.

Form D: During normal operations, the movement of trains is governed solely by the signal and computerized dispatch system. However, in some circumstances (such as failure of the signal system), an alternate method of controlling the movement of trains is needed. This is done with a system of 'warrants' - a warrant is filed for the train and track in question and those warrants are kept by both the train crew and the dispatcher. By referring to the warrants in effect, the dispatcher and train crew have confirmation of what track they are authorized to operate on. Under the NORAC rules (see NORAC below), a track warrant is known as a Form D. The form has specific numbered line items, which act as a checklist for the dispatcher and train crew. Sometimes you can hear a dispatcher give the required entries for a Form D to a train crew - for example, in the case of a failed grade crossing gate, a Form D may be required for the train to proceed past the grade crossing, and the Form D will specify the slower speed or other precautions that must be taken. The Form D is entered into a computer at the dispatcher end, but that is not 'interlocked' to the CTC (see above) - the dispatcher must manually insure that adequate protections exist for whatever situation is requiring the Form D. On the train crew end, the Form D is an actual piece of paper that must be filled out, and it cannot be filled out while the train is moving. If you hear a train crew refer to a delay related to paperwork at a location 'out on the line' away from South Station, chances are they are receiving a Form D from the dispatcher over the radio. When departing a terminal to begin a trip, you will typically hear the conductor tell the engineer: "No D's, no changes, OK to proceed on signal indication." The reference to "D's" is telling the engineer that no Form D's are in effect for the trip.

Framingham Subdivision: The freight line (now owned by MASS DOT) that leads from Framingham through Sherborn to Walpole and Mansfield, where it connects to the Northeast Corridor. The switch off the Framingham Worcester mainline is just to the east of the Concord Street crossing and within the limits of the CP 21 interlocking in downtown Framingham. There is currently one round trip CSX freight train to/from Framingham and Mansfield on this line. B731 departs Framingham around 11 PM and heads south to Mansfield (and eventually to Readville via the Northeast Corridor). It returns to Framingham in the AM, and usually heads west through Framingham station to Nevins Yard between P506 and P508 (about 7:30 AM). It holds south of Blandin Avenue until the Worcester Line dispatcher gives it permission to proceed onto the main line (if it pulled all the way up to near the main line, it would foul (block) the Blandin Avenue grade crossing, tying up vehicle traffic in South Framingham). Sometimes, if it is a short train with not as many freight cars as usual, it will run up to Nevins Yard between P582 and P506 (about 7:00 AM).

Frequency: see Channel above.

GPS: Global Positioning System. Each train has a GPS receiver that is used to transmit it's position back to Keolis Customer Service via the PTIS system (see below). Note that this GPS data is NOT used to dispatch and control trains.

Grade crossing: railroad term for intersection of train tracks and automobile roads. All of the grade crossings on the Framingham-Worcester line are protected by gates and flashers, and there are no 'quiet zones' on the line (quiet zones are locations where trains do not blow their whistles as a warning at grade crossings). The Framingham-Worcester line has only five grade crossings over 45 track miles. Listed from east to west:Bishop Street, Framingham (milepost 20.9)Concord Street, Framingham (milepost 21.3)Main Street, Ashland (milepost 24.2)Cherry Street, Ashland (milepost 24.4)Parmenter Lane, North Grafton (milepost 37.4)In the eastbound direction, the grade crossing at Concord Street in Framingham is usually manually activated for commuter rail trains. See "DTMF" above.

Grade: Hill, slope, change in elevation. Because trains have limited traction between the wheels and the rails, even a small grade can be difficult for a train to traverse, especially if the train has to go up a grade from a standing stop (such as at a station). See "sand" below.

Grand Junction: A single track rail line that connects the south side to the north side, via the Beacon Park freight yard, a bridge over the Charles River, and tracks that run through Cambridge (close to MIT). The Grand Junction is used for regular freight service. It is also used by Keolis / MBTA to reposition trains between the south side and the north side, especially to get equipment to and from the BET / CRMF (see above). Amtrak uses it to reposition equipment from the "Downeaster" service (between North Station and Maine) and their Southhampton Street maintenance facility on the south side. There is no passenger service on the grand junction, so you can't see it on regular MBTA maps. The Grand Junction is under the jurisdiction of the Keolis north side terminal dispatcher. You can see the Grand Junction on this map.

Head End Power ("HEP"): On a freight train, the locomotive only produces electricity for the locomotive. There is no electricity distributed to the freight cars. The brake system on the freight cars uses compressed air, so there is a hose connection between each freight car and the locomotive to distribute this compressed air, but other than the actual couplers holding the train together, the compressed air hose is the only connection between freight cars on a freight train. However, on a passenger train, electricity is needed in each coach (for lights, HVAC, etc.). Locomotives used for passenger trains, therefore, have a separate system to provide electricity to the coaches. This system is known as the head end power. On older locomotives (such as the F40 types), the HEP is an actual separate diesel engine coupled to an AC (alternating current) generator. On the newer locomotives (the HSP-46 types), the HEP is just an inverter that takes the DC power produced by the main engine and converts it to AC. [Actually, the new HSP-46 locos have 6 inverters. 4 are used to provide AC power to the traction motors, and 2 are used to provide "HEP" for the coaches.] The electricity produced by the HEP is distributed throughout the train via a "MU" (Multiple-Unit) cable (see below) (passenger coaches also use compressed air for the braking system, so there is also a compressed air hose connecting each coach and the locomotive to the coaches). The HEP system helps to explain some of the different failure modes of the locomotives. If your train is being pulled by an older F40 series, then the failure of the HEP system does not necessarily prevent the locomotive from moving, since the HEP is separate from the 'prime mover' engine. Likewise, failure of the prime mover on an F40 does not result in a loss of lights or HVAC in the coaches. However, for a train with a HSP-46 locomotive, failure of the prime mover diesel engine will disable everything - the HEP inverter will have no power, and the traction motors will have no power. But failure of the HEP inverter on a HSP-46 will not prevent the traction motors from moving the train. The one big caveat to this theory is that the HEP (on both older and newer locomotives) provides electricity for the control stand in the control coach. So in push mode, where the train is being operated from the control coach, loss of the HEP may result in the train being disabled since the engineer will not be able to operate the controls. Head end power Wikipedia article here.

High Ball: Throwback term meaning 'clear signal.' An artifact of the original way of displaying a clear signal to an oncoming train at a manually operated signal - literally, a ball raised to the highest point.

High Car Detector: Similar to a defect detector (see above), this device detects an overheight locomotive, freight car, or passenger coach before it can strike a bridge. Years ago, the bridges on the Framingham - Worcester line between Worcester and Framingham were upgraded to a higher clearance primarily for autorack freight cars that were previously unloaded in the "CP" yard in South Framingham. The Boden Lane bridge just east of the West Natick station was not raised and is therefore a height restriction for anything coming east from Worcester (or points west). A high car detector (with a setting of 17' 2.5") is on an overhead structure in downtown Framingham - just east of CP 21, right in front of the old Dennison Manufacturing building. This high car detector is linked to the flashing white ("lunar") wayside signal lights just west of the West Natick station. If an overheight car is detected, the flashing light will turn solid - and an engineer who sees this must stop the train and then inspect the train to determine why it is overheight.

Home Signal: The signal controlling entrance into an interlocking. This signal can be controlled by the dispatcher (as opposed to automatic block signals (see above). A home signal typically has no signs or markings on it (unless it is also a distant signal for the next interlocking - see "Distant Signal" above). There are specific rules for a home signal (as opposed to an automatic block signal) - for example, all red at a home signal is a stop and go no further while all red at an automatic block signal is "stop and proceed." See also "NORAC" above.

Interlocking: A set of signals that are interlocked to prevent erroneous operation. For example, the signals in an interlocking can be programmed such that they will not allow 'proceed' or 'clear' signals to be displayed if switches are misaligned. In common usage (especially on the Framingham-Worcester line), the term "interlocking" refers to the physical collection of signals and switches within each Controlled Point (see CP above), since each interlocking is a CP, and also has a set of switches. The 'limits' of the interlocking are the furthest points outside of these switches, and marked with signals. The switches and the signals at each interlocking are remotely controlled by the dispatcher (and also automatically linked to the Automatic Block Signal system). The Framingham-Worcester line is widely known for having an insufficient number of interlockings. The number of interlockings was reduced while Conrail was the operator, in an effort to reduce the complexity and cost of the line. Also, the frequency of train traffic did not require a large number of interlockings. More interlockings increase the flexibility of routing trains.

K-Car: Kawasaki built double level coach. See "double" above.

Lake Shore Limited: The name of the Amtrak train that serves the Boston to Chicago route via our Framingham - Worcester line. Wikipedia article here. Amtrak.com page here. There is one trip daily (7 days a week) in each direction. The train provides passenger service stops at Worcester, Framingham, Back Bay, and South Station, and doesn't stop at any other stations between Worcester and Boston. It is possible to buy a ticket between Worcester and Boston, but not between Worcester and Framingham or Boston and Framingham (presumably since the MBTA offers Framingham service, Amtrak can't or won't provide service on that 'commuter' portion). One could buy a Boston to Worcester ticket and just get off at Framingham...although this 'hidden city' ticketing is against the Amtrak rules. A passenger could save about a half hour by taking the outbound midday Lake Shore Limited to Framingham or Worcester instead of P517 on the current MBTA schedule. I've never tried it...Another interesting note about this train is that it actually has a "Y" type of route. The eastbound train from Chicago is actually physically split at Albany with some coaches (and passengers!) going south to New York City while some coaches and passengers go east to Boston. Similarly, the westbound train from Boston meets up with the northbound train from New York City and joins to become one train set to Chicago from Albany.​This train is sometimes deridingly called the "LATE Shore Limited," due to its historically terrible schedule performance. For example, in the 12 months from October 2014 to September 2015, it was on-time only 38% of the time (click here for on-time performance metrics). Logically, the westbound departure from Boston is usually on-time in our area, while the eastbound arrival from Chicago is more likely to be late (due to the accumulated delays of the long trip). The schedule as of April 2015 has the following daily (including weekends) schedule in the Boston area:Westbound from Boston to Chicago:Depart South Station: 12:50 PMBack Bay: 12:57 PMFramingham: 1:25 PMWorcester: 2:03 PMEastbound from Chicago (via Albany):Worcester: 6:44 PMFramingham: 7:12 PMBack Bay: 7:52 PMSouth Station: 8:01 PM

Layover: Overnight 'parking' for a train set on a dedicated siding where it can be plugged into ground power. At the current time, the Worcester MBTA yard has capacity to layover 4 train sets. No trains currently layover in Framingham or anywhere else on the line. Aerial photo of Worcester layover yard.

Mechanical Help Desk: See "Channel" above. ​Mini-High: The small section of raised platform that allows handicapped / direct access into a coach without a need to climb the steps of the trap (see below). The section of the mini-high platform closest to the train is removable. As related in a previous blog post: "Speaking of freight trains, the manager claims that approximately once a month, CSX moves wide load freight trains from Worcester to Framingham. This requires Keolis to 'drop' the removable high level platforms from the 'min-high' platforms at Worcester, Grafton, Westborough, Southborough, and Ashland. Once in Framingham, the freight trains can be routed into the freight yards (bypassing the actual Framingham station) and then usually go north or south from Framingham (not east past the West Natick station). I always knew why those platforms were removable, but I had no idea that wide loads were so frequently moved across the line. You may also notice that the Yawkey station was constructed with full length permanent high level platforms. This will prevent wide load freight trains from moving past Yawkey - and the removal of 'freight rights' over that section of track was part of the Yawkey station project. What's a wide load on a freight train? There are lots, like these planes that get moved across the western US (unless they fall into a river), but we're more likely to see electrical transformers."As long as freight trains are permitted to share the line with the commuter trains, full high platforms (such as at South Station and Yawkey) are less likely, due to the complexity of the required removable sections. Even at a station like Back Bay, where a full high platform could be installed, it is unlikely to be installed due to budgetary constraints.

MU (Multiple-Unit) Cable: A short cable used to connect the locomotive to the coaches and the coaches to each other. Spare MU cables can frequently be seen hanging around the platforms at South Station. The MU cable is used to transmit electricity from the HEP (see above) in the locomotive to the coaches. The MU cable also carries control signals to and from the control stand in the control coach (or between two locomotives in the case of a multiple locomotive consist). The sockets where MU cables connect can be seen next to the coupler on the end of coaches or locomotives. An MU cable is needed to hook up one train to another, and therefore each train set is supposed to have a spare MU cable (and air hose) on board in case connections need to be made 'in the field' (away from the infrastructure and support of a terminal or maintenance facility, which would probably have plenty of cables and hoses hanging around). A missing MU cable (or air hose) from a broken-down train and its designated rescue train contributed to the delay of a third train on December 18, 2015. See here for the blog post about that story.

Non-Revenue: Movement of a train set from one place to another, BUT without passengers. Sometimes also called a "deadhead" move. A non-revenue move can be a regularly 'scheduled' move with specific times, but it won't be on the public MBTA schedule (it would be on the employee timetable). Non-revenue moves also don't show up on the GPS tracking apps. Non-revenue moves can also be 'extras' when it is needed to move equipment from one place to another outside the normal schedule.

NORAC: Northeast Operating Rules Advisory Committee. A consortium of various railroads developed common operating rules in an effort to improve safety and interoperability. Those rules are commonly known as the "NORAC" rules. The latest edition of the rule book is the 10th edition. The rules govern everything including employee conduct, the meaning of signals, speed limits, and the operation of trains on the railroad. See also Form D above.Wikipedia article here.

Northeast Corridor: Sometimes referred to as just the "Corridor," the Northeast Corridor is the Amtrak train line that stretches from Boston to Washington DC. From Boston to Wickford Junction (RI), the MBTA Providence line shares the route with Amtrak. There are a series of dispatchers (all Amtrak employees) at the South Station CETC (see "CETC" and "Dispatcher" above) responsible for the Northeast Corridor from New Haven, CT to Boston, and those dispatchers handle all traffic on the Corridor including commuter rail, freight, and Amtrak trains. These dispatchers sit in the CETC theatre in South Station - and the dispatch software and computer systems for the Corridor from New Haven CT to Boston are in South Station. An agreement between the MBTA and Amtrak allows Amtrak to use the Massachusetts owned rail line from the Rhode Island border to Boston for free, in exchange for Amtrak providing dispatch and maintenance services for the line. The Corridor has overhead catenary (power lines) for Amtrak trains, including the Acela Express. Along an 11 mile stretch from just north of Mansfield station to just south of Attleboro station, the authorized speed of the Acela is 150 mph. This is one of only a few places the Acela reaches its maximum speed - the fastest speed of any train in the United States. See also "ACSES" above. The Framingham-Worcester line parallels the Corridor from Back Bay to South Station (on the opposite side of the Orange Line tracks). Wikipedia article here.

North Side: The network of rail lines originating from North Station.

Notch: Unlike a car's accelerator, which can be depressed in a smooth continuous action, the throttle of a locomotive has eight notches that correspond to the amount of electrical power applied to the traction motors (with one being the lowest amount of power and eight being the highest). Electronics in the locomotive speed up the prime mover engine to provide increased power as higher notches are selected. See also Diesel-Electric and Traction Motor.

Old Colony Lines: The Greenbush, Kingston/Plymouth, and Middleboro commuter rail lines; so called because they were operated by the Old Colony RR previous to being taken over by the New Haven system. Largely abandoned in late 1950's and restored in the 1990's as traffic mitigation for the Big Dig. These are the newest lines in the commuter rail system, and they are constructed for high speeds and the stations all have high level platforms. Because they have all high level platforms, the coach doors can be remotely operated from a single position - like a subway car - so passengers can board at any door, not only one with a conductor standing next to it. Only some coaches are equipped with these remotely operated automated doors, and those coaches are identifiable by the lack of exterior door handles and a yellow 'D' after each car's road number. Therefore train sets with all automated doors remain assigned to the Old Colony lines and are not usually interchanged with the other lines on the south side. Automated door coaches are sometimes mixed in with other south side line consists. Old Colony lines do not serve Back Bay station.

Pax: common Twitter abbreviation for "passengers."

Penalty Brake Application: The automatic application of the brakes by the locomotive / control coach electronics in response to a failure by the engineer to respond properly to a signal or some other operational consideration. For example, if the engineer exceeds the speed limit for the signal displayed by the cab signal (see above), the brakes will be applied. A brake application as a result of not responding to the deadman switch (see above) is also a penalty brake application. It is called a penalty brake application not because some kind of disciplinary action is taken against the engineer but rather because a certain set of steps must be undertaken by the engineer to release the brakes and resume normal operations. This may or may not involve the train coming to a full stop. It should be noted that an equipment malfunction can also cause a penalty brake application - for example, if communication is lost between the fixed 'track-side' cab signal system and the on-board 'train-side' cab signal system, a penalty brake application could result. The penalty brake application system is designed to be a redundant safety system. So not all penalty brake applications are the 'fault' of an engineer.

Plate "X": Various railroads have differing clearances around their tracks (such as different bridge heights). In order to allow for a standard reference among the different railroad companies, the Association of American Railroads (AAR) adopted a uniform system of classifying the 'loading gauge' of railcars using the "plate" system. Rail routes can be designated by the maximum plate clearance allowed, which allows for easy determination of the suitability for a railcar over a particular line. All freight railcars must be marked with their plate letter - some say "plate x" while some just have the letter. The various plate dimension diagrams are here. Wikipedia article here.

Positive Train Control (PTC): Another complex (and controversial) topic that really requires its own page. But oversimplified to a ridiculous extent, PTC is an automated system that prevents trains from doing things they shouldn't do. Essentially it is a backstop in the case of an engineer making a mistake. For example, if a train (and train line) is equipped with PTC, and the train were to pass a stop signal, the PTC system would take control and automatically stop the train. The Framingham-Worcester line does not yet have this functionality, although it is mandated (by federal law) to be installed by 12/31/2018 (for all trains everywhere). The MBTA has announced plans to comply with this mandate (except the Providence line, which already has ACSES for PTC (see above)). In late December 2015, the MBTA awarded a $338 million contract to implement PTC on the entire commuter rail system. Press release here. There is a good news report here about the implementation of PTC on the last section of the Northeast Corridor that didn't have it - in Philadelphia. The news report includes a demonstration of PTC / ACSES (see above) in the Amtrak simulator. PTC Wikipedia article here. Generally speaking, PTC is the highest form of signalling and train control available. Over history, the progression of signals and controls went generally like this, from oldest and least complex to newest and most complex:1) Track side employees manually changing flags or some sort of signal at points along the line (see "High Ball" above)2) Automatic block signal systems (see above)3) Cab signals (see above)4) Positive Train Control

Prime Mover: The engine within the locomotive that produces the energy needed to run a generator that produces electricity for the traction motors. All MBTA commuter locomotives have a diesel engine as the prime mover. See Diesel-Electric above.

Private Varnish: Privately owned rail car, used for chartered (or just the owner's private) excursions. Private varnish railcars can occasionally be observed at South Station where they serve as 'hotels' while their passengers spend the day / weekend in Boston. Assuming they meet certain Amtrak standards, private varnish railcars are typically towed by regularly scheduled Amtrak trains from point to point. Anyone can charter the private varnish railcars that are available for charter (some are not chartered out by their owners) - but the cost is not quite within reach for the average family - see this article. However, there are some opportunities to purchase a single 'berth' / seat / room on private varnish trips. Most are listed here. The American Association of Private Railroad Car Owners is probably the best source of information - they publish a magazine about the private varnish 'industry.' Private varnish Wikipedia article here.

PTIS: Passenger Train Information System. This is the system that transmits GPS data from each train back to MBTA / Keolis Customer Service and also automatically out to all of the apps and websites we use. It is also linked to the LED sign system at each station, to the "Rail Radio" system (see below), and to the on-board train announcements ("next stop is..."). The on-board PTIS can be manually reset by conductors on the train, but it is usually automated and does not require the conductors to do anything (even when a train turns). This is why trains arriving at South Station start saying silly things like "the destination of the this train is Readville," even when the train hasn't fully arrived in South Station. That's the PTIS automatically resetting for the next trip. The on-board PTIS can also be remotely reset by Keolis from a central location. The PTIS system is NOT linked to the dispatch system, so it is NOT used in the formal dispatch / control system for trains. It is just for gathering information so Keolis can share that info with customers (either manually in the case of text / tweet alerts or automatically in the case of app data). Keolis actually uses a combination of PTIS data and dispatch information to generate the text alerts and tweets about delayed trains. Each control coach (see above) has a PTIS system - that way each train has one PTIS since most trains only have one (and only one) control coach.

Push-Pull Mode: In the old days, before control coaches existed, a train could only operate in one direction. The train would have to be turned around at each end of its trip to keep the locomotive in front. Alternatively, a locomotive could be attached to either end of the train. Both methods are obviously very inefficient. The control coach solves this problem by allowing the train to be 'pulled' out of Boston with the locomotive in the lead and then 'pushed' back to Boston with the control coach in the lead. Most commuter rail systems and even Amtrak operate trains in push-pull mode. Wikipedia article here.

QB: Prefix applied to all mileposts along the Framingham-Worcester line from Boston to Worcester. Actually the QB mileposts go across the entire former Boston & Albany line all the way to near Albany, New York. Mileage is measured from 0 at South Station, but the first mile of track is within the Northeast Corridor and those mileposts are named according to that system. The first named / referenced QB milepost is just west of CP COVE (see Controlled Point above). When Conrail owned and operated the line, mileposts were simply referred to as "MP." When Conrail was dissolved and CSX acquired the Boston & Albany line, the mileposts were eventually renamed according to a CSX naming convention in order to avoid the confusion of all train lines having "MP" mileposts. All former Conrail lines were given the first letter "Q" and a second letter that usually corresponded to some historical name of the line - "B" for Boston & Albany in our case. Hence the "QB" mileposts were born. Details here.

Rail Radio: Low power AM radio transmitters at some stations that transmit information about trains to waiting passengers. It uses data from the PTIS system. More info here. Does anyone use this? I've never heard of anyone who uses it.

Readville Switcher: Slang term for the overnight assignment of a work locomotive to shuttle locomotives and coaches between the Readville maintenance facility, the South Side Service & Inspection Facility (near Widett Circle), South Station, and the BET (see above) via the Grand Junction. If you are at South Station anytime after the evening commute, you may see the Readville Switcher at South Station as it moves equipment around. The Readville switcher occasionally ventures farther out (primarily to Middleboro or Rochester) to deliver or retrieve equipment to/from maintenance and/or storage facilities.

Restricted speed: the slowest, most conservative movement that is allowed / defined by the NORAC rules (see above). Three conditions are set out in NORAC rule 80 which govern movement at restricted speed, and paraphrasing / simplifying them:a) must be able to stop the train within half the range of vision to avoid an obstruction or problem (so a train might have to really crawl around a curve if the sight lines are blocked);b) maintain a lookout for broken rail and misaligned track;c) can't exceed 20 mph outside of an interlocking or 15 mph within an interlocking (see "interlocking" above).

Riverside: Most people think of Riverside as the end of the "D" branch of the green line. However, the entire above grade portion of the "D" line is just a former big 'loop' off of our Framingham Worcester line (eventually known as the "Highland Branch." Before it was used for trolleys, it was a regular rail line. It started at a switch off of the main line at the location of the present day Yawkey station. When the "Highland Branch" was reconfigured to connect to the underground subway system in downtown Boston, this switch was removed and a tunnel was extended from Beacon Street to just beyond Miner Street where the Green line tracks emerge to follow the "Highland Branch" towards Newton. See this page for a good diagram showing the present day path of the Green line near Yawkey station.The "Highland Branch" rejoined the main line at a switch very close to the Charles River in Newton. That switch, now known as the "Riverside" switch, still exists and is between CP 11 (see Weston Switch below) and the Auburndale station. The Riverside switch area has been used most recently as a staging area for the construction crews involved in the rail destressing project (see Heat Restrictions above). The Riverside switch is actually a physical connection between the Green line and the Framingham - Worcester line, and the rules that regulate "light rail" (Green line) and regular commuter rail equipment require that the physical connection be interrupted. Various methods have been used to maintain this separation over the years, including a pile of sand / gravel, derailers, and other physical obstacles. A locked fence gate now separates the Green line from the Framingham Worcester line at the Riverside switch. The section of track within the fenced area has overhead catenary (electric wires) for Green line trolleys. That section of track leads directly to the Riverside Green line station, and is sometimes used for training, testing, or storage of cars. You can see the fenced-in area with the overhead catenary from the Framingham Worcester main line as you pass by the Riverside switch. From October 23-25, 1996, a temporary platform was constructed and used for special commuter rail train service from Riverside to Boston after heavy flooding at the Fenway portal closed the entire "D" branch. Here is a great photo of a green line trolley and commuter rail engine on the same tracks. The Wikipedia article about the "D" line includes the entire history of the "Highland Branch."Riverside was also a station on the Framingham Worcester line, separate from the Riverside station we know today on the Green line. You can still see the remnants of the station if you look closely as the trains pass by the Riverside switch. Just to the west of the switch on the south side of the tracks are both a stairway leading down below grade and a paved platform.

Rotem: See "Double" above.

Rule 241: This rule (see NORAC above) is used to allow a train to pass a stop signal in conjunction with a radio conversation between the dispatcher and the train. Use of this rule does not require issuing a Form D (see above). Note that if a train is issued permission to pass a stop signal under Rule 241, the train must proceed at 'restricted speed' (see above) to the next signal. There are other rules that you may overhear referred to in radio conversations between the dispatcher and the engineer or conductor, but this is one of the most common.

Sand: Grainy stuff that gets in your beer at the beach. Also the stuff that is stored inside each locomotive and dispensed via small tubing onto the point of contact between the locomotive wheels and the rail in order to increase the traction between the wheels and the rails, especially in the case of autumn slippery rails or slippery rails due to rain, snow, or ice. Small piles of sand can sometimes be observed next to the tracks within stations where too much sand was dispensed. The sand can be dispensed automatically when the locomotive senses wheel slip or manually by the engineer. Wikipedia article here.

Screamer: Slang term for the older F40PH locomotive type that had no separate diesel engine to drive the HEP generator (see above). The HEP generator on these locomotives was driven directly by gear connected to the prime mover - and because the HEP needed to be run at a constant speed to generate electricity for the coaches, the prime mover needed to be run at a (high) constant speed - hence these locomotives were always 'screaming.' The last of these locomotives were taken out of service in 2015 when the new HSP46 locomotives were delivered and placed into service. See the NETransit Roster for more info on locomotive inventory.

Set or Consist: a combination of a locomotive and coaches that forms a train.

S&I: Service and Inspection. Usually a reference to the "S&I" tracks at the Amtrak Southhampton Street Yard. You may overhear the "Amtrak Terminal" dispatcher (see "dispatcher" above) talking to a train crew and sending them to "S&I #3" or "S&I #4," which are the storage tracks outside the Amtrak service buildings (S&I #1 and #2 go through the Amtrak S&I maintenance building). Through an arrangement with Amtrak, Keolis / MBTA uses some of the Amtrak tracks at their yard to store trains during the mid-day hours. It's an obvious solution: most of the Amtrak fleet is out on the road during the middle of the day traveling to New York and Washington DC, leaving those tracks empty and unneeded. But quite a few MBTA / Keolis train sets need storage in Boston between the AM rush and the PM rush. At night, the condition is reversed - Amtrak trains are being stored in Boston, while the MBTA / Keolis trains are being stored at distant 'layover' yards awaiting the AM rush. See this document for more about layover and maintenance facilities.

Single: See "flat" above.

Slippery Rail: A condition where the rails become slippery in the autumn due to the breakdown of leaves on the rails. This can cause wheel slip (see below) or in extreme cases, engine burn (see above). It can also cause a train to slide past a stop. Slippery rail can be enough of a problem to prevent a train from starting from a stop, especially if going up even a slight grade. On the Framingham-Worcester line, there is a slight uphill grade leaving the Natick Center station, which can be problematic during slippery rail season. The stations in Wellesley seem to be more prone to slippery rail effects, certainly due to the proximity and abundance of trees near the line. Keolis created acute little cartoon video describing the problem and the 'rail washer' they use to combat / mitigate the slippery rail. Keolis also published this brochure. Slippery rail Wikipedia article here. See also "sand" above. People like to chuckle and think slippery rail must be a joke, just because it sounds so laughable that leaves could stop trains, but it isn't a joke - it's a serious, legitimate problem on many railroads around the world.

South side: The network of rail lines originating from South Station.

SRO: Common Twitter abbreviation for "Standing Room Only" - as in train crowded, all seats taken, passengers standing in aisles.

Starter: The first signal departing the South Station platforms, at the far end of each platform (away from the South Station headhouse). Technically this is a home signal for the "Tower 1" interlocking. You may hear the South Station terminal dispatcher tell a train "OK down to the starter" which means the train can start moving out of the station since the signal will change momentarily.

Superelevation: In order for trains to go around curves at high speeds without flying off the tracks, the outside track is elevated so that the train will 'lean' into the curve. Same idea as the elevated curvature of a NASCAR race track or a highway exit ramp. This is called superelevation and there is a specific formula related to the radius of the curve and the speed limit of the train through the curve that is used to calculate the angle of the superelevation. On the Framingham Worcester line, the station at Auburndale is on a relatively short radius curve where the speed limit is 60 mph. Therefore the track is super elevated at about 3 degrees. Normally superelevation is not noticeable if a train is travelling close to the speed limit - but when a train makes the station stop at Auburndale, those 3 degrees makes it seem as though the train will topple over (it won't)!

Tower 1: Interlocking (see above) just outside of South Station that encompasses all the switches that allow trains coming from any line to go to any platform in South Station. Each line that comes into South Station has a signal to enter the Tower 1 interlocking, and sometimes due to trains crossing ahead, an inbound train will be stopped at that signal for a few minutes. On the Framingham-Worcester line, the inbound (eastbound) Tower 1 signal is just past where the tracks start to curve into South Station. The Tower 1 signals on the Framingham Worcester line are at the same point as the Tower 1 signals on the Northeast Corridor, so trains from Worcester and Providence are sometimes both stopped at Tower 1 right next to each other. On Thursday, February 18, 2016, Tower 1 died and caused enormous problems for all South Side commuters. I explained more about Tower 1 and what happened in a blog post about the Tower 1 failure. Adam Gaffin of universalhub.com posted a couple of fascinating follow-up blog posts about the history of Tower 1: post 1 here and post 2 here.

Trainmaster: The Keolis manager responsible for managing the fleet of commuter rail equipment. These responsibilities include keeping track of which train sets have sufficient fuel for their trips or shuffling train sets in the case of break downs or problems. Conductors or engineers will confer with the "trainmaster on duty" when they encounter an issue at South Station and need a management decision (or assistance resolving a problem). The trainmaster at South Station sits in the bubble (see above).

Trainman: See Assistant Conductor above.

Traction Motor: The actual electric motor that turns the axles connected to the drive wheels on a locomotive. All modern day locomotives (freight and passenger) use electric motors to drive the wheels. Most locomotives have one traction motor for each drive axle, hence all MBTA locomotives have 4 traction motors, since they all have four drive axles! The traction motors are located at the axles, making them very susceptible to ingesting snow (especially fine powdery snow). Once ingested, the heat of the motors melts the snow into water, and water and electric motors is not an ideal combination. See also Diesel-Electric above.

Trap: the movable platform over the set of stairs that allows passengers to climb onto and off the coach down to a grade level platform. The trap is left closed when the coach is aligned with a high level platform so passengers can walk directly onto or off the coach. Federal Railway Administration rules require traps and outer doors to be in the closed and stowed position before a train can be moved. Those rules also state that only train crew members can operate the traps. Back in the good old days (prior to maybe 2004?) all the traps and doors were left open and we passengers could embark and disembark anywhere we wanted to. While it was convenient, I observed some slightly scary 'near misses' related to unsupervised boarding and exiting of trains - lots of people would get off trains while they were rolling to a stop, since you could walk right down the steps while the train was still approaching the station. See also "vestibule" below.

Turn: the process of changing one set of equipment from an outbound to an inbound (or vice versa) train.

Upgrade: the change in the condition of a signal from a more restrictive condition to a less restrictive condition. For example, if an engineer approaching a signal sees it change from "approach" (similar to a yellow traffic light) to "clear" (similar to a green traffic light), that would be an 'upgrade.' Since the engineer is required to tell the conductor the condition of any signal less than clear, using the term 'upgrade' makes it clear that the signal changed to something better. See also Automatic Block Signal above.

Vestibule: the unheated space at the end of each coach that contains the trap (see above). As per Federal Railway Administration rules, it is illegal for a train to be operated with passengers occupying the vestibules, since the vestibules are designed as 'crumple zones' in the case of a collision.

Wayside Signal: A signal post / tower / mast on the side of the tracks.

Weston Switch: Dave's nickname for the set of switches / interlocking at CP 11. See "interlocking" and "CP" above. CP 11 is in the town of Weston, alongside Recreation Road and the Leo J. Martin golf course, just west of Route 128, between Auburndale Station and Wellesley Farms Station. This interlocking is a critical element of the Framingham Worcester line because it is the only set of cross over switches between Framingham and Boston - therefore It provides the only place where trains can switch from track 1 to track 2 which might be needed for a number of reasons:1) Provide service to the Newton stations, which only have a platform on track 2;2) Align rush hour trains on track 2 between Wellesley Farms and Framingham;3) Provide a place for the two 'leapfrog' express trains (P582 and P583) to switch onto the other track in order to go around parallel traffic; and4) Provide a place for trains to switch to another track due to a disabled train (or flooded track, or blocked track, or broken track, etc.) on one track.

West Station: new station proposed to be built in conjunction with realignment of Mass Pike in Allston. See this blog post and then read this one.

Wheel Slip: The advantage of trains and railroads is the minimal steel to steel contact between the train and the rail, which allows for very low friction - hence very good efficiency (did you see the CSX TV commercial: Moving one ton of freight 423 miles on one gallon of fuel? And do you believe it?). This advantage is also a disadvantage - it can be very difficult to get a train moving, especially up a hill or with 'slippery rails' (see above). Because there is such low friction, the locomotive wheels can start to slip and spin - see this video for an extreme example. Also notice in that video that you can see the middle axle on the lead truck of the lead locomotive start to slip at the beginning of the video - before the ridiculous spinning sparking wheels. Wheel slip can lead to "engine burn" (see above) if the locomotive doesn't move enough. Some locomotives are equipped with automatic limiters which sense slip and reduce power to the motors. Locomotives are also equipped with sand to dispense onto the track to increase friction. See "sand" above.

Wye: An arrangement of tracks in a "Y" formation that allows for the direction of a train to be reversed. Similar to a three point turn in a car.